As computer programs and data files have become larger and larger, and take up more and more space on portable data storage devices (such as floppy disks), it has become increasingly common to store these programs and files on compact disks ("CD's"). While early CD's did have the advantage of being able to store very large amounts of data, they suffered from the disadvantage that it was not possible for the consumer to record his or her own data on the CD. Thus, only pre-recorded CD's were available. Recently, however, "re-writable" CD's have started to become available. The consumer can record data on these CD's and, when desired, can erase that data and/or record new data over the old. Re-writable CD's, therefore, are much like traditional floppy disks, except that they can store much greater quantities of information.
One concern with re-writable CD's is that there be a means by which accidental erasure of recorded information can be avoided. Floppy disks solve this problem by providing a movable tab which, when it is in one position, prevents additional information from being recorded on the disk and prevents erasure of any information from the disk. One means by which this can be accomplished on a re-writable CD is by covering the File Allocation Table (FAT) section of the CD.
A good write-protect component must be both inexpensive to manufacture and easily removable from the CD so that, if desired, a previously write-protected disk can be recorded on again.